NASA Will Reveal Secrets of Clouds and Aerosols

Two NASA satellites, planned for launch no earlier than Oct. 26, will give
us a unique view of Earth's atmosphere. CloudSat and Cloud-Aerosol Lidar and
Infrared Pathfinder Satellite Observations (Calipso) are undergoing final
preparations for launch from Vandenberg Air Force Base, Calif.

CloudSat and Calipso will provide a new, 3-D perspective on Earth's clouds
and airborne particles called aerosols. The satellites will answer questions
about how clouds and aerosols form, evolve and affect water supply, climate,
weather and air quality.

CloudSat and Calipso employ revolutionary tools that will probe Earth's atmosphere.
Each spacecraft carries an "active" instrument that transmits pulses of energy and
measures the portion of the pulses scattered back to the instrument.

CloudSat's cloud-profiling radar is more than 1,000 times more sensitive than
typical weather radar. It can detect clouds and distinguish between cloud particles
and precipitation. "The new information from CloudSat will answer basic questions
about how rain and snow are produced by clouds, how rain and snow are distributed
worldwide and how clouds affect the Earth's climate," said Dr. Graeme Stephens, CloudSat
principal investigator at Colorado State University, Fort Collins, Colo.

Calipso's polarization lidar instrument can detect aerosol particles and can distinguish
between aerosol and cloud particles. "With the high resolution observation that Calipso
will provide, we will get a better understanding of aerosol transport and how our climate
system works," said Dr. David Winker, Calipso principal investigator at NASA's Langley
Research Center, Hampton, Va.

The satellites will be launched into a 705-kilometer (438-mile) circular, sun-synchronous
polar orbit, where they will fly in formation just 15 seconds apart as members of NASA's
"A-Train" constellation with three other Earth Observing System satellites. The A-Train
includes NASA's Aqua and Aura satellites and France's Polarization and Anisotropy of
Reflectances for Atmospheric Sciences coupled with observations from a Lidar satellite.

The usefulness of data from CloudSat, Calipso and the other A-Train satellites will be
much greater when combined. The combined set of measurements will provide new insight
into the global distribution and evolution of clouds that will lead to improvements in
weather forecasting and climate prediction.

CloudSat is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif. The radar instrument
was developed at JPL, with hardware contributions from the Canadian Space Agency. Colorado
State University provides scientific leadership and science data processing and distribution.

Other contributions include resources from the U.S. Air Force and the U.S. Department of Energy.
Ball Aerospace and Technologies Corp. designed and built the spacecraft. A host of U.S.
and international universities and research centers provides support to the science team.
Some of these activities are contributed as partnerships with the project.

Calipso was developed through collaboration between NASA and the French Space Agency, Centre
National d'Etudes Spatiales. NASA's Langley Research Center leads the Calipso mission and
provides science team leadership, systems engineering, payload mission operations, and validation,
processing and archiving of data. Langley also developed the lidar instrument in collaboration
with the Ball Aerospace and Technologies Corp., which developed the onboard visible camera.